U.S. patent number 6,995,839 [Application Number 10/681,039] was granted by the patent office on 2006-02-07 for automated raman scanner for documents and materials.
Invention is credited to Frederick W. Shapiro.
United States Patent |
6,995,839 |
Shapiro |
February 7, 2006 |
Automated Raman scanner for documents and materials
Abstract
A scanner employs Raman spectroscopy for on site automated
materials authenticity verification and identification. A
technology developed so that operators with little or no technical
expertise can perform on site fast nondestructive materials
analyses. Automated generation of Raman signatures, and subsequent
correlation to spectral fingerprints of known materials provides an
ideal means for documentation verification or materials
identification in settings like airport ticket counters, U.S.
Customs gates, law enforcement vehicles and business offices (such
as a physician's examination room). Computer controlled moveable
optics provides for a scanning capability to automatically and
precisely analyze several locations on a sample. The Raman scanner
also provides for on site materials analysis requiring a high level
of technical expertise to be done by transmission of the spectral
data to a remote location via modem or wireless communications
using a transmitter and receiver.
Inventors: |
Shapiro; Frederick W. (Fairfax,
VA) |
Family
ID: |
35734268 |
Appl.
No.: |
10/681,039 |
Filed: |
October 8, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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60416853 |
Oct 8, 2002 |
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Current U.S.
Class: |
356/301;
356/71 |
Current CPC
Class: |
G01J
3/44 (20130101); G01N 21/65 (20130101); G07D
7/1205 (20170501); G01N 2021/656 (20130101); G01J
3/0264 (20130101) |
Current International
Class: |
G01J
3/44 (20060101); G01N 21/65 (20060101); G06K
9/74 (20060101) |
Field of
Search: |
;356/301,71
;355/122,99,84 ;399/377,380,17,9 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Toatley, Jr.; Gregory J.
Assistant Examiner: Chisdes; Sarah J.
Attorney, Agent or Firm: Fortkort; Michael P Michael P
Fortkort PC
Parent Case Text
STATEMENT OF RELATED APPLICATION
This application claims the benefit of priority to U.S. Provisional
Patent Application No. 60/416,853, filed Oct. 8, 2002 by the same
inventor, and entitled "Automated Raman Scanner."
Claims
What is claimed is:
1. An apparatus for performing on-site automatic nondestructive
materials analysis on a subject using Raman spectroscopy
comprising: a Raman scanner including: one or more laser light
sources to illuminate the subject, a charge coupled device camera
to capture emitted radiation from the subject, and an optical path
to direct the emitted radiation from the subject to the charge
coupled device camera; a database to store a plurality of spectral
fingerprints of known samples; and a processor coupled to the
scanner to compare a spectral signature in the emitted radiation
from the subject to the plurality of spectral fingerprints of known
samples in the database; an optical sensor coupled to the processor
to detect a presence or absence of the subject; a memory, wherein
upon said optical sensor automatically sensing removal of the
subject, said processor saves a spectral signature from the subject
in the memory and resets for a next subject.
2. The apparatus according to claim 1, wherein said processor
generates a "positive/negative" or a "best match" response and
forwards a result to an operator.
3. The apparatus according to claim 1, further comprising one or
more optical probes for scanning a particular subject that does not
conform to a scanning surface.
4. The apparatus according to claim 1, further comprising computer
readable media having encoded thereon instructions that cause the
processor to automate capture and correlation of a Raman signature
of the subject to spectra in the database and determine a best
match or matches within a predetermined confidence level, wherein
if no matches are found within the predetermined confidence level a
"No Match Found" response will be generated and forwarded to the
operator.
5. The apparatus according to claim 1, further comprising computer
readable media having stored thereon spectral correlation software
to enable the processor to provide on site automated material
identification.
6. The apparatus according to claim 1, further comprising computer
readable media having stored thereon spectral correlation software
to enable the processor to provide on site documentation
authenticity verification.
7. The apparatus scanner according to claim 1, further comprising
computer readable media having stored thereon spectral correlation
software to enable the processor to provide capability to
automatically trace a material to its origin using a database of
known Raman signatures.
8. The apparatus scanner according to claim 1, further comprising
moveable optics controlled by the processor to provide materials
analysis of more than one point along the subject without
physically moving the subject.
9. The apparatus according to claim 1, wherein said processor
automatically generates Raman spectra of one or more points on the
subject and correlates them to spectra in the database of known
materials.
10. The apparatus according to claim 1, further comprising a
communications device to transmit one or more results.
11. The apparatus according to claim 1, wherein the scanner
includes a scanning surface and one or more optical probes having
conjugated optics to enable scanning of a subject that does not
conform to the scanner surface.
12. The apparatus according to claim 1, wherein the scanner
includes a scanning surface and one or more forms for accurate
positioning of the subject on the scanner surface.
13. The apparatus according to claim 1, wherein the scanner
includes an adaptor that conforms to a subject surface profile to
insure that no ambient light contaminates a subject spectral
signature.
14. The apparatus according to claim 1, further comprising computer
readable media having stored thereon software to enable the
processor to filter out erroneous spectral features in a sample
signature.
15. A method for analyzing a subject comprising: scanning the
subject with a Raman scanner; detecting an emitted radiation from
the subject; determining a spectral signature of the emitted
radiation from the subject; and comparing the spectral signature of
the emitted radiation from the subject against one or more samples
to determine if the spectral signature of the emitted radiation
matches one of the one or more samples; and detecting removal of
the subject and automatically saving the spectral signature in
memory and resetting for a next subject.
16. The method according to claim 15, further comprising generating
a "positive/negative" or a "best match" response and forwarding a
result to an operator.
17. The method according to claim 15, further comprising detecting
a presence of the subject and automatically initiating said
scanning upon detecting the presence of the subject.
18. The method according to claim 15, wherein said scanning
includes scanning one or more points on the subject without
physically repositioning the subject.
19. The method according to claim 15, wherein said scanning
includes using one or more optical probes for scanning a particular
subject that does not conform to a scanning surface.
20. The method according to claim 15, wherein said comparing
includes correlating a Raman signature of the subject to spectra in
a database and determining one or more best matches within a
predetermined confidence level, if no matches are found within the
predetermined confidence level generating a "No Match Found"
response, and forwarding the one or more best matches or the "No
Match Found" response to the operator.
21. The method according to claim 15, further comprising providing
on site automated material identification.
22. The method according to claim 15, further comprising providing
on site documentation authenticity verification.
23. The method according to claim 15, further comprising providing
capability to automatically trace a material to its origin using a
database of known Raman signatures.
24. A method for analyzing a subject comprising: automatically
generating a Raman spectra of one or more points on the subject;
and comparing the spectral signature of the emitted radiation from
the subject against one or more samples to determine if the
spectral signature of the emitted radiation matches one of the one
or more samples; and detecting removal of the subject and
automatically saving the spectral signature in memory and resetting
for a next subject.
25. The method according to claim 24, further comprising
transmitting the spectral signature over a communications link for
analysis.
26. The method according to claim 24, further comprising using one
or more forms to accurately position the subject on a scanner
surface.
27. The method according to claim 24, further comprising placing an
adaptor on the subject that conforms to the subject surface profile
to ensure that no ambient light contaminates a subject spectral
signature.
28. The method according to claim 24, further comprising filtering
out erroneous spectral features in a sample signature.
Description
FIELD OF THE INVENTION
The present invention is directed to methods and apparatuses for
automated non-invasive examination, and more particularly to a
method and apparatus for non-invasive examination using optical
scanning and Raman spectroscopy.
BACKGROUND
Individuals and organizations seek to transfer materials and
mis-identified people through a country's borders without detection
by the border officials. Thus, a need exists for simple, rapid
detection of contraband materials and forged documents.
The present invention is therefore directed to the problem of
developing a method and apparatus for scanning objects and
documents in a quick yet effective manner, which can be
accomplished using a portable device.
SUMMARY OF THE INVENTION
The present invention solves these and other problems by providing
a portable, automatic Raman scanner that compares a spectral
signature of a sample against a database of known spectral samples
to identify suspicious materials or documents.
According to a first aspect of the present invention, an apparatus
for performing on-site automatic, nondestructive materials analysis
on a subject using Raman spectroscopy includes a Raman scanner, a
database and a processor. The Raman scanner employs one or more
laser light sources that illuminate the subject via an optical
path. The Raman scanner includes a highly sensitive charge coupled
device camera to collect emitted radiation. The database stores
spectral fingerprints of known samples. The scanner automatically
generates a spectral signature from the subject and the processor
compares the generated spectral signature to the known samples in
the database.
According to another aspect of the present invention, the processor
may generate a "positive/negative" or a "best match" response based
on a statistical algorithm and forward the result to an
operator.
According to still another aspect of the present invention, the
apparatus may include a memory in which the processor can save the
spectral signature, thereby enabling the processor to reset for a
next sample.
According to another aspect of the present invention, one or more
points on the subject can be scanned without physically
repositioning the subject.
According to yet another aspect of the present invention, the
apparatus may also include one or more optical probes for scanning
a particular subject that does not conform to a scanning
surface.
According to still another aspect of the present invention, the
apparatus may also include computer readable media having encoded
thereon instructions that cause the processor to automate capture
and correlation of a Raman signature of the subject to spectra in
the database and determine a best match or matches within a
designated confidence level, wherein if no matches are found within
the designated confidence level a "No Match Found" response may be
generated and forwarded to the operator.
According to a further aspect of the present invention, the
apparatus may also include computer readable media having encoded
thereon spectral-correlation software to enable the apparatus to
provide: capability to automatically trace a material to its origin
using a database of known Raman signatures; on site documentation
authenticity verification; or on site automated material
identification or verification.
According to still another aspect of the present invention, the
apparatus may also include computer controlled moveable optics to
provide materials analysis of more than one point along a subject
without physically moving the subject. In this case, the processor
may automatically generate Raman spectra of one or more points on
the subject and correlate them against spectra in the database of
known materials.
According to yet another aspect of the present invention, the
processor may automatically detect a presence of the subject on a
scanner surface and initiate generation of a spectral signature. In
this case, the processor may also sense removal of the subject and
then store a spectral signature and automatically reset for a next
subject.
According to another aspect of the present invention, the apparatus
may include a battery to power it, thereby making the apparatus
portable.
According to still another aspect of the present invention, the
apparatus may include a communications device to transmit the
results to a central location.
According to another aspect of the present invention, the Raman
scanner may include one or more optical probes that utilize
conjugated optics for subjects that are inaccessible or do not
conform to the scanner surface.
According to yet another aspect of the present invention, the
scanner may include one or more forms for accurate positioning of a
subject on the scanner surface.
According to another aspect of the present invention, the scanner
may include more than one source laser.
According to a further aspect of the present invention, the scanner
may include an adaptor that conforms to a subject surface profile
to insure that no ambient light contaminates a subject spectral
signature.
According to still another aspect of the present invention, the
apparatus may include computer readable media having encoded
thereon software to filter out erroneous spectral features in a
sample signature.
According to another aspect of the present invention, a method for
analyzing a subject includes scanning the subject with a Raman
scanner, detecting an emitted radiation from the subject,
determining a spectral signature of the emitted radiation from the
subject, and comparing the spectral signature of the emitted
radiation from the subject against one or more samples to determine
if the spectral signature of the emitted radiation matches one of
the one or more samples.
According another aspect of the present invention, a
"positive/negative" or a "best match" response may be generated and
forwarded to an operator.
According another aspect of the present invention, a presence of
the subject may be detected thereby automatically initiating the
scanning upon detecting the presence of the subject. Furthermore,
removal of the subject may be detected thereby initiating
automatically saving of spectral signature in memory and resetting
for a next subject.
According another aspect of the present invention, one or more
points on the subject may be scanned without physically
repositioning the subject.
According another aspect of the present invention, one or more
optical probes may be used for scanning a particular subject that
does not conform to a scanning surface.
According another aspect of the present invention, the comparing
includes correlating a Raman signature of the subject to spectra in
a database and determining one or more best matches within a
predetermined confidence level, if no matches are found within the
predetermined confidence level generating a "No Match Found"
response, and forwarding the one or more best matches or the "No
Match Found" response to the operator.
According another aspect of the present invention, on site
automated material identification, on site documentation
authenticity verification, and tracing of a material to its origin
is made possible.
According to another aspect of the present invention, a method for
analyzing a subject includes automatically generating a Raman
spectra of one or more points on the subject, and comparing the
spectral signature of the emitted radiation from the subject
against one or more samples to determine if the spectral signature
of the emitted radiation matches one of the one or more
samples.
According another aspect of the present invention, the spectral
signature may be transmitted over a communications link for
analysis.
According another aspect of the present invention, one or more
forms may be used to accurately position the subject on a scanner
surface.
According another aspect of the present invention, an adaptor may
be placed on the subject that conforms to the subject surface
profile to ensure that no ambient light contaminates a subject
spectral signature.
According another aspect of the present invention, erroneous
spectral features may be filtered in a sample signature to improve
accuracy of the results.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts an exemplary embodiment of a Raman Scanner in a top
view according to one aspect of the present invention.
FIG. 2 depicts an internal view of an exemplary embodiment of a
Raman Scanner Standard Operation Mode according to another aspect
of the present invention.
FIG. 3 depicts an internal view of an exemplary embodiment of the
Raman Scanner Optical Probe Operation Mode according to yet another
aspect of the present invention.
FIG. 4 depicts an exemplary embodiment of a method for scanning a
subject according to another aspect of the present invention.
FIG. 5 depicts an exemplary embodiment of a method for scanning a
subject according to another aspect of the present invention.
DETAILED DESCRIPTION
It is worthy to note that any reference herein to "one embodiment"
or "an embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment of the invention. The
appearances of the phrase "in one embodiment" in various places in
the specification are not necessarily all referring to the same
embodiment.
These embodiments of the present invention address form, fit, and
function modifications to conventional Raman spectrographic
technology resulting in an automated Raman scanner to be used for
on site material identification and verification. Mechanical,
optical and software modifications and enhancements are made to
conventional Raman spectrographic technology to permit this
capability.
The Raman scanner of the present invention enables fast,
nondestructive analysis in an automated manner to on-site materials
in a non-laboratory environment. The Raman scanner function is
automated to be user-friendly and requires very little user
training or technical expertise. The Raman scanner is capable of
being portable and battery powered. The Raman scanner can
accommodate both large and small sized samples.
The form of the scanner provides a surface similar to a bar code
scanner to analyze smaller objects. Mechanical forms are included
for applications where positioning of the subject is critical to
achieve a spectral signature required for accurate identification
or verification.
An example of the use of forms includes personal identification
verification in an airport environment. To verify the authenticity
of a passport or driver's license, it is imperative to scan the
appropriate portion or portions of the documentation. A form (e.g.,
an outline or depression into which the document is placed) ensures
proper alignment of the document in the scanner. The document will
be placed in the scanner and scanned either automatically or via
operator prompt on a laptop computer.
Optical probes are included to analyze large or immobile subjects
that do not conform easily to the scanner surface. Conjugated
optics are used to collect and guide light into and out of the
optical probes. The scanner surface and the optical probes are
fitted with adapters that conform to the shape of the subject to
prevent ambient light from contributing to the Raman spectrum of
the sample.
Optical modifications can be made to suit each particular
application. The source laser wavelengths selected can be based on
the materials of interest for each individual application. Optics
selection is optimized for sample spectra signature strength and
scanner design parameters, such as size, weight, and power
consumption. The optical path is modified from conventional Raman
technology to accommodate a scanner form and function similar to a
bar code reader. Raman scanners are adapted to include more than
one laser if the application includes multiple distinct sample
types requiring more than one source wavelength.
An example of this occurs at a customs gate where both personal
identification verification and drug identification are required. A
highly sensitive CCD camera is used to detect emitted radiation
based on the source laser wavelengths.
Software modifications enable conventional laboratory Raman
spectrographic technology to be converted to an on-site automated
materials analysis capability. The scanner is employed in
conjunction with a laptop or stand-alone computer system.
User-friendly software prompts the operator to place the sample in
the scanner. The scanner detects that a sample is in place and
automatically scans the subject.
Software enhancements permit automatic selection of a number and
location of points to be scanned on each subject type. Data
acquisition software enables a Raman spectral signature to be
automatically generated for the subject. The resulting Raman
spectral signature may be automatically compared to control spectra
in a database for authenticity verification or material
identification.
A "positive/negative" response is generated based on a high
confidence level and provided to the operator for authenticity
verification, such as in passport validation. A "best match" list
may be provided to the operator along with degree of confidence for
material identification, such as in drug analysis. If the match is
below a preset confidence threshold, the computer may post a "No
Match Found" result.
The scanner senses removal of the sample and automatically resets
for a next subject. All sample signatures can be automatically
catalogued and saved.
Optionally, the embodiment can include a communications device via
which Raman signatures of negative responses may be transmitted to
a remote location for further analysis by trained operators. This
communications device can include a modem or wireless
communications device. Identification of a manufacturer origin of
the sample may then be achieved by comparison of the subject Raman
spectral signature to databases of known samples.
The form of the Raman scanner is modified to exhibit a minimal
footprint to fit easily in a relatively small space. The type of
setting in which the scanner will be used may require limited space
and ease of accessibility such as an airport ticket counter, U.S.
Customs gate, law enforcement vehicle, or a medical office.
FIG. 1 shows a top view of an exemplary embodiment 10 of a Raman
Scanner according to a first aspect of the present invention. The
scanner surface 1 is composed of a transparent material that
contributes no spectral features in the fingerprint region of the
spectrum. Many glass materials would be suitable. Form 2 depicted
in FIG. 1 is a form designed for each subject. The purpose of the
form is to insure accurate alignment of the subject on the scanner
surface 1. The form 2 may take alternate sizes and shapes depending
on the particular application and the positioning accuracy
required. An optical sensor 3 is used to alert the system that a
subject has been placed on the scanning surface 1 and is ready to
be analyzed. The optical sensor 3 initiates the automated analysis
process. Ports 4, 5, 6 are interfaces to interface the scanner
laser, CCD camera, and optics-positioning controller, respectively,
with a laptop or standalone computer 7. Interface port 8 is an
interface port for optical probes used to analyze large or immobile
subjects that are unsuitable for the scanning surface 1.
FIG. 2 depicts an exemplary embodiment 20 of the scanner operation.
Computer controlled moveable optics are incorporated to permit
scanning of more than one point without the need to physically
relocate the subject, if required, for accurate identification or
verification. A subject such as a passport is placed on the scanner
surface 21. The edges 22a, 22b of the form position the subject so
that the correct portion of the material is scanned. The sensor 23
detects presence of a subject and initiates the materials analysis.
Laser source 24 has a wavelength and intensity selected for the
particular application. The laser light is transmitted to a
moveable mirror 25, which then redirects the light to the correct
location on the scanner surface 21. The rotating feature of the
mirror 25 permits the laser light from laser source 24 to
illuminate the surface of the subject in more than one location if
desired. Raman radiation scattered back through the scanner surface
21 from the test subject is captured by the moveable optics 26, 27,
28 and 29 and is focused on a CCD camera 32. Optics 26, 27 and 29
are reflecting mirrors used to capture and focus the emitted
radiation from the subject. Optics 28 is a grating selected for the
particular application to disperse the shifted wavelengths of
emitted radiation. Controller 31 is used to drive the moveable
optics.
The controller 31 is commanded by the laptop or standalone computer
system 7. Spectral data collected by the CCD camera 32 is
transmitted to the laptop computer 7 and analyzed. The laptop 7
automatically searches pre-selected spectral databases and uses
correlation software to determine the "best matches" within a
specified confidence level if any exist. The result is
automatically transmitted to the operator. The optical sensor 23
senses the removal of the test subject and automatically resets the
scanner for the next subject. The spectral fingerprint(s) of the
test subject is automatically saved and catalogued.
Optical probes 38 may be included to analyze large or immobile
subjects that will not conform easily to the scanner surface. FIG.
3 depicts an exemplary embodiment 30 of an internal view of the
scanner operation using the optical probes. The source laser 24 has
a wavelength and intensity selected for the particular application.
The laser light is focused on the optical probe port 34, which is
then transmitted to the test subject via conjugated optics and
optical probes 38. The optical probes 38 will be made of a graded
index material selected for low loss over the operating wavelength
range and will contribute no spectral features into the subject
Raman signature. Scattered Raman radiation is captured via
conjugated optics and transmitted back through the probes to the
optics 33, 35, 28 and 29 and focused on a CCD camera 32. Optics 33,
35 and 29 are reflecting mirrors used to capture and focus the
emitted radiation. Optics 28 is a grating selected for the
particular application to disperse the different wavelengths of
emitted radiation.
Spectral data collected by the CCD camera 32 is transmitted to the
laptop computer 7 and analyzed. The laptop 7 automatically searches
the pre-selected spectral databases and uses correlation software
to determine the "best matches" within a specified confidence level
if any exist. The result is automatically transmitted to the
operator. The spectral fingerprint(s) of the test subject is
automatically saved and catalogued.
FIG. 4 depicts an exemplary embodiment 40 of a method for analyzing
a subject.
At step 41, one or more optical probes are used for a subject that
does not conform to a scanning surface.
At step 42, a presence of a subject to be scanned for on site
automated material identification, documentation authenticity
verification, or origin tracing is detected.
At step 43, one or more points on the subject are scanned, without
necessarily repositioning the subject using a Raman scanner, upon
detecting the presence of the subject on the scanner.
At step 44, emitted radiation is detected from the subject.
At step 45, a spectral signature of the emitted radiation from the
subject is determined.
At step 46, the spectral signature of the emitted radiation from
the subject is compared against one or more samples to determine if
the spectral signature of the emitted radiation matches one of the
one or more samples. This can be accomplished by, for example,
correlating a Raman signature of the subject to spectra in a
database and determining one or more best matches within a
predetermined confidence level. If no matches are found within the
predetermined confidence level a "No Match Found" response is
generated.
At step 47, a "positive/negative" or a "best match" response, or a
No Match Found response is forwarded to an operator.
At step 48, removal of the subject is detected and the spectral
signature is automatically saved in memory and the system is reset
for a next subject.
At step 51, one or more forms are used to accurately position the
subject on a scanner surface.
At step 52, one or more optical probes are used for a subject that
does not conform to a scanning surface.
At step 53, an adaptor is placed on the subject that conforms to
the subject surface profile to ensure that no ambient light
contaminates a subject spectral signature.
At step 54, erroneous spectral features are filter out of a sample
signature.
At step 55, a presence of a subject to be scanned for on site
automated material identification, documentation authenticity
verification, or origin tracing is detected.
At step 56, a Raman spectrum is generated from one or more points
on the subject.
At step 57, the spectral signature is transmitted over a
communications link for analysis.
At step 58, the spectral signature of the emitted radiation from
the subject is compared to one or more samples to determine if the
spectral signature of the emitted radiation matches one of the one
or more samples. This can be accomplished by, for example,
correlating a Raman signature of the subject to spectra in a
database and determining one or more best matches within a
predetermined confidence level. If no matches are found within the
predetermined confidence level a "No Match Found" response is
generated. The one or more best matches or the "No Match Found"
response is then forwarded to the operator.
Although various embodiments are specifically illustrated and
described herein, it will be appreciated that modifications and
variations of the invention are covered by the above teachings and
are within the purview of the appended claims without departing
from the spirit and intended scope of the invention. For example,
certain applications of the Raman Scanner herein are discussed, but
the invention is not limited to these applications as other
applications would be apparent from review of this application.
Furthermore, these examples should not be interpreted to limit the
modifications and variations of the invention covered by the claims
but are merely illustrative of possible variations.
* * * * *